Hope Diamond

Grading the Hope

For many years, the weight of the Hope Diamond was not precisely known, with reports of its weight ranging from 44 carats to 45.5 carats. On November 13, 1975, the Hope Diamond was removed from its setting and found to weigh 45.52 carats.

Gemologists from the Gemological Institute of America (GIA) visited the Smithsonian in 1988 to grade the Hope Diamond. They observed that the gem showed evidence of wear, that it had a remarkably strong phosphorescence, and that its clarity was slightly affected by a whitish graining that is common to blue diamonds. They described its color as fancy dark grayish-blue and its clarity as VS1 (Crowningshield 1989).

In 1996, the Hope Diamond necklace was sent to Harry Winston, Inc. for cleaning and minor restoration work. The diamond was removed from its setting and re-examined by the GIA. In this report, the Hope's color was described as a a natural fancy deep grayish-blue (reflecting a change in GIA's nomenclature for grading, not a change in the assessment of the diamond).